Electron discharge tube and the like



MarchBO, 1937. J JACKMAN 2,075,761

' ELECTRON DISCHARGE TUBE AND THE LIKE Filed Sept. 28,, 1936 Alllk wilw w l V NTOR ATTORNEY Patented Mar. 30, 1937 PATENT OFFICE ELECTRON DISCHARGE TUBE AND THE LIKE Joseph J. Jackman,

Hygrade Sylvania Corporation,

Danvers, Mass, assignor to Salem, Mass, a

corporation of Massachusetts Application September 28, 1936, Serial No. 102,875

5 Claims.

This invention relates to electron discharge tubes and more particularly to improvements in means to support and space the electrodes in a device such as a radio tube or the like.

Heretofore in radio tubes and similar devices employing a plurality of electrodes which must be maintained accurately and firmly spaced, it has been customary to employ a mica disc, or ceramic block to receive the projecting ends of the electrode side-rods or other projections attached to the electrodes. Accordingly it is one of the principal objects of the present invention to provide an improved manner of fastening the usual insulator spacer member to the side-rods or other parts of the tube mount.

- A feature of the invention relates to an improved arrangement for fastening a metal member to an insulator member by employing a specially shaped tab or strap which facilitates welding, and at the same time provides a firm connection whereby tilting of the insulator member with respect to the metal member is substantially avoided.

A further feature relates to the novel organization, arrangement and relative location of parts which go to make up an improved insulator spacer and support member for radio tube mounts and the like.

Other features and advantages not specifically enumerated will be apparent after a consideration of the following detailed descriptions and the appended claims.

While the invention will be described herein as embodied in one particular form of radio tube it will be understood that this is done merely for explanatory purposes and not by way of limitation. Consequently the invention may be embodied in a wide variety of electrical devices without departing from the spirit of the invention. Accordingly in the drawing Fig. 1 is an elevational view, partly in section, of a radio tube embodying the invention.

Fig. 2 is an enlarged top plan view of part of the mount of Fig. 1.

Fig. 3 is an end View of Fig. 2.

Fig. l is a sectional view of Fig. 2 taken along the line L- i thereof.

Fig. 5 is a sectional view of Fig. 3 taken along the line 5-5 thereof.

Fig. 6 is an enlarged detail view of one of the fastening members shown in the preceding figures.

Referring to Fig. 1 there is shown a typical radio tube comprising an enclosing envelope l to which is sealed the press or header 2 carrying the various lead-in and support wires 3 to 9 inclusive and the electrode assembly, it being understood that in certain respects the showing of Fig. 1 is essentially diagrammatic. Merely for purposes of explanation the tube shown in Fig. 1 is of the triode type comprising a filamentary cathode ID, a helically wound wire grid H, and a tubular metal plate or anode l2. The grid II is formed with a pair of parallel uprights or side-rods 13, M, and the plate I2 is provided with a similar pair of uprights or side-rods I5, IE, it being understood that the turns of the helical wire grid are fastened to the side-rods l3, M in any well-known manner, and likewise the side-rods l5, l6 are fastened to the plate l2. The filament has its free ends fastened, preferably by welding to the wires 5, I while the bight of the filament is supported from the upper end of the upright 6, which preferably extends upwardly outside the plate l2. Preferably also a spring hook I l is fastened to the upper end of member 6 and engages the bight of the filament to maintain the latter under the proper tension.

For the purpose of maintaining the upper ends of the various electrodes in their proper spaced relation, there is provided an insulator spacer member l8 preferably, although not necessarily, in the form of a mica disc having a series of perforations as shown in Fig. 2. An elongated central perforation I9 is provided to allow the tension hook I! to pass therethrough and to engage the filament bight. The perforations 20, 2| are provided to allow the grid side-rods l3, M toproject therethrough as shown in Fig. 1. Likewise, the perforations 22 are provided to allow the plate side-rods l5, It to project therethrough. Preferably these perforations are of substantially the same size as the associated side-rods so as to provide a tight fit. The mica is also provided at each end adjacent the perforations 22, with two sets of perforations 23, 24 to receive the metal tab members 25 and 26.

As shown in detail in Fig. 6, each of the tab members is formed from a single length of wire having a raised or offset portion 2'! intermediate its ends, which ends are bent at right angles as shown in Fig. 6. The distance between the ends 28 and 29 is equal to the distance between the perforations 23, 24 and the tab membersare assembled as shown in Figs. 3 and 4, so that the straight portions 30, 3| rest against the face of the mica and with the portions 28, 29 projecting through the perforations 23, 24. The end portions 28, 29 are then bent back upon themselves as shown in Figs. 3 and 4, so as to grip the mica firmly, it being understood that the tab members are assembled so that their planes are perpendicular to the plane of the mica. Preferably the perforations 23, 24 are so proportioned and located that when the mica, with the tabs clinched thereon, is assembled on the ends of side-rods i5, I6, the said side-rods are very close to and preferably touch the offset portions 21. The said side-rods may then be Welded to the said offset portions 21, thus providing a rigid connection between the tabs and the side-rods.

The foregoing construction provides a threepoint connection between each tab and the mica and since the side-rod passes through the mica in an oifset position with respect to the tab, the mica is at all times maintained perpendicular to the side-rod. Furthermore by reason of the fact that the middle portion of the tab is offset or raised, it is convenient to insert a welding tool to effect the welding of the tab to the side-rod. While the drawing (Fig. 1) shows only two tabs whereby the mica is fastened to the side-rods 65, "5 it will be understood that if desired similar tabs may, if desired, be used to fasten the siderods l3, 14 to the mica. Likewise while the drawing shows a tube mount with only a single mica at the top of the mount, it will be understood that a similar mica may be mounted at the bottom of the mount and secured thereto by tabs similar to those described. This method of fastening is well-suited to those tubes employing ceramic block spacers instead of mica spacers, since it has always been a difficult matter to employ metal eyelets with such ceramic block spacers, and it will be obvious that the tabs as shown may be employed with spacers of any desired thickness. Various changes and modifications may be made without departing from the spirit and scope of the invention.

What I claim is:

1. In an electrode assembly the combination of an insulator member, a ,support rod passing through said member, a metal tab having its ends fastened to said member and having a portion intermediate its ends offset from said member, said offset portion being fastened to said side-rod.

2. In an electrode assembly the combination of an insulator member having a set of three openings, a support rod passing through one of said perforations, and a metal tab having its ends passing through the other two of said openings, the ends of the tab being bent back to grip said member, said tab having a portion intermediate its ends offset from the insulator member and Welded to the side-rod.

3. In an assembly of the character described the combination of an insulator member, a wire tab having its ends clinched to said member and having a portion intermediate its ends offset with respect to said member, a perforation in said member, and a side-rod passing through said perforation and welded to said offset portion.

4. In a radio tube mount the combination of a plurality of electrodes at least one of said electrodes having a side-rod, a mica spacer having a perforation to allow said mica to be positioned adjacent the end of said electrodes with the said side-rod passing therethrough, a Wire tab having its ends clinched to said mica spacer and having a portion intermediate its ends offset with respect to the mica to facilitate welding of the said side-rod to said tab.

5. A spacer assembly for a radio tube mount comprising an insulator member, a pair of metal wire tabs each having its ends clinched to the insulator member and each having an offset portion, each insulator member being provided with a side-rod perforation adjacent to but offset with respect to the associated tab.

JOSEPH J. JACKMAN. 

